Suction nozzles for cleaning purposes have been used before, but exclusively in conjunction with smooth-surfaced, i.e., noncorrugated, filter elements, in spite of the obvious advantages offered by the corrugated elements which facilitate the accommodation, in a given filter-housing size, of a much larger filter surface. The reasons for this state of affairs is the prevailing opinion that cleaning by suction is simply not suitable for corrugated filter elements, an opinion that has taken root due to the absence, so far, of proven rules that would establish clear relationships between principal filter-element and suction-nozzle parameters which, if adhered to, would ensure efficient cleaning, by suction nozzles, also of corrugated filter elements.
It is an object of the present invention to remedy the above-described situation by establishing such a relationship as can be used in the design of filters with corrugated elements that can be efficiently cleaned by means of suction nozzles.